Add pptx_optimize_images tool (#85)

.squad/agents/cheritto/history.md

@@ -154,3 +154,15 @@
 - **Files:** PresentationService.Deduplication.cs (new partial), PptxTools.Deduplication.cs, DeduplicateMediaResult.cs, DeduplicateMediaTests.cs
 - **Build:** 0 errors; 542/542 tests passing (10 new tests)
 - **PR:** on branch squad/84-deduplicate-media
+
+### Issue #85 — pptx_optimize_images (2026-03-26)
+- **Implementation:** Phase 4 Tier 2 write operation — compresses/optimizes images by downscaling, format conversion, and recompression
+- **Dependency:** Magick.NET-Q8-AnyCPU v14.2.0 (cross-platform ImageMagick wrapper, Apache 2.0 license per Nate's research)
+- **Key logic:** Read image dimensions with MagickImageInfo → find Picture shape via Blip.Embed → extract display dimensions from Transform2D.Extents → calculate target dimensions based on targetDpi (EMU → pixels: emu / 914400 * dpi) → downscale if pixel dimensions exceed display dimensions → convert BMP/TIFF to PNG/JPEG → recompress JPEG at specified quality → only replace if optimized size < original
+- **Type challenges:** MagickImageInfo returns uint for Width/Height; MagickImage.Resize() requires uint; MagickImage.Width/Height properties are uint; model uses int — required explicit casts throughout
+- **Namespace aliasing:** Used `P = DocumentFormat.OpenXml.Presentation` and `A = DocumentFormat.OpenXml.Drawing` to resolve ambiguous Picture/BlipFill references
+- **Models:** ImageOptimizationResult with OptimizedImageInfo; reuses ValidationStatus from RemoveLayoutsResult.cs
+- **Files:** PresentationService.ImageOptimization.cs (new partial), PptxTools.Optimization.cs (added tool method), ImageOptimizationResult.cs
+- **Build:** 0 errors; 542/542 tests passing (no new tests yet — Shiherlis owns test creation)
+- **PR:** #93 on branch squad/85-optimize-images
+

.squad/agents/nate/history.md

@@ -250,3 +250,33 @@
 **Deliverable:** `.squad/decisions/inbox/nate-phase4-openxml-research.md` — 40 KB comprehensive research with code sketches, gotchas, validation strategies for all 7 issues.
 
 **Impact:** Unblocks Phase 4 implementation planning. Team can now scope work with confidence: #80–#82 are quick wins; #83–#84 require diligent testing; #85 is optional enhancement; #86 safely deferred.
+
+### 2026-03-26: Magick.NET Feasibility Research — Issue #85 (Image Compression)
+
+**Research Scope:** Jon directive to investigate Magick.NET (instead of SkiaSharp) for issue #85 image compression/optimization tool. Evaluate feasibility, cross-platform support, bundle size, API surface, and integration with PresentationService.
+
+**Key Findings:**
+- **Verdict: GO** ✅ — Magick.NET is fully viable for #85. Covers all requirements (resize, re-encode JPEG quality 85%, convert BMP/TIFF→PNG/JPEG, read dimensions, stream-based I/O)
+- **Licensing:** Apache-2.0 (permissive, commercial-friendly, OSI-approved)
+- **Cross-Platform:** Full Linux support on ubuntu-latest; bundles static-linked native binaries (no separate ImageMagick install needed)
+- **Recommended Package:** `Magick.NET-Q8-x64` v14.11.0+ (Q8=8-bit component, x64=platform-specific, reduces bundle size)
+- **Bundle Size Impact:** ~15-18 MB added to published binary (AnyCPU variant would be ~27-35 MB). Acceptable for open-source MCP server.
+- **API Strength:** Clean Magick.NET surface for all operations:
+  - Dimensions: `MagickImageInfo.Width`, `MagickImageInfo.Height`
+  - Resize: `image.Resize(width, height)` with aspect ratio control
+  - JPEG Quality: `image.Quality = 85` before `image.Write()`
+  - Format Conversion: `image.Format = MagickFormat.Jpeg` / `MagickFormat.Png`
+  - I/O: Stream-based (`new MagickImage(stream)`, `image.Write(outputStream)`)
+- **Integration Pattern:** Create `PresentationService.ImageOptimization.cs` with public `OptimizeImages()` tool method; thin wrapper around Magick.NET with in-place image replacement via `imagePart.FeedData(stream)`
+- **Magick.NET vs. SkiaSharp:** Magick.NET slower for simple resize (SkiaSharp 2-4x faster) but superior for image compression workflow: richer format support (100+ formats), JPEG quality control, BMP/TIFF handling. Bundle size tradeoff acceptable; performance not a bottleneck for one-time optimization.
+- **Risks:** Native library compatibility on Linux (mitigated by .csproj properties for binary bundling), aspect ratio preservation (use `Resize(width, 0)` for auto-height), JPEG quality trade-offs (document as expected for compression)
+- **Implementation Estimate:** 6-8 hours (dependency setup, tool method, E2E test, README update)
+
+**Deliverable:** `.squad/decisions/inbox/nate-magick-net-research.md` — 10 KB feasibility report with API sketches, integration pattern, bundle size breakdown, comparison table vs. SkiaSharp, gotchas, and handoff recommendations for Cheritto.
+
+**Impact:** Unblocks #85 decision. Go/no-go clear; Jon's Magick.NET preference validated. Ready for development phase with high confidence in approach.
+
+**File Paths:**
+- `src/PptxMcp/Services/PresentationService.Media.cs` (lines 104–145) — current image traversal pattern (Foundation for new ImageOptimization.cs)
+- NuGet: https://www.nuget.org/packages/Magick.NET-Q8-x64/
+- Magick.NET GitHub: https://github.com/dlemstra/Magick.NET (reference for API/cross-platform docs)

README.md

@@ -85,6 +85,7 @@ See [docs/QUICKSTART.md](docs/QUICKSTART.md) for a full walkthrough.
 | `pptx_find_unused_layouts` | Find unused slide masters and layouts with estimated space savings |
 | `pptx_remove_unused_layouts` | Remove unused slide layouts and orphaned masters with before/after validation |
 | `pptx_deduplicate_media` | Deduplicate identical media by hash, redirect references, remove orphaned copies |
+| `pptx_optimize_images` | Compress/optimize images by downscaling, format conversion, and recompression |
 
 **When to use `pptx_update_slide_data` vs `pptx_update_text`:** Use `pptx_update_slide_data` when shapes have descriptive names (check `pptx_get_slide_content`) — it targets shapes by name and preserves their existing formatting. Use `pptx_update_text` for anonymous placeholders identified only by index.
 

src/PptxMcp/Models/ImageOptimizationResult.cs

@@ -0,0 +1,49 @@
+namespace PptxMcp.Models;
+
+/// <summary>Details about a single optimized image.</summary>
+/// <param name="ImagePath">Package URI of the image part.</param>
+/// <param name="OriginalFormat">Original image format (PNG, JPEG, BMP, TIFF, etc.).</param>
+/// <param name="OptimizedFormat">Format after optimization.</param>
+/// <param name="OriginalWidth">Original image width in pixels.</param>
+/// <param name="OriginalHeight">Original image height in pixels.</param>
+/// <param name="OptimizedWidth">Width after downscaling (same as original if not downscaled).</param>
+/// <param name="OptimizedHeight">Height after downscaling (same as original if not downscaled).</param>
+/// <param name="OriginalSizeBytes">Original image size in bytes.</param>
+/// <param name="OptimizedSizeBytes">Size after optimization in bytes.</param>
+/// <param name="BytesSaved">Bytes saved by optimization.</param>
+/// <param name="Action">Description of action taken (downscaled, converted, recompressed, skipped).</param>
+public record OptimizedImageInfo(
+    string ImagePath,
+    string OriginalFormat,
+    string OptimizedFormat,
+    int OriginalWidth,
+    int OriginalHeight,
+    int OptimizedWidth,
+    int OptimizedHeight,
+    long OriginalSizeBytes,
+    long OptimizedSizeBytes,
+    long BytesSaved,
+    string Action);
+
+/// <summary>Structured result for pptx_optimize_images.</summary>
+/// <param name="Success">True when the operation completed without errors.</param>
+/// <param name="FilePath">Path to the modified presentation file.</param>
+/// <param name="ImagesProcessed">Number of images that were optimized.</param>
+/// <param name="ImagesSkipped">Number of images that were skipped (no optimization possible).</param>
+/// <param name="TotalBytesBefore">Total size of all images before optimization.</param>
+/// <param name="TotalBytesAfter">Total size of all images after optimization.</param>
+/// <param name="TotalBytesSaved">Total bytes saved by optimization.</param>
+/// <param name="OptimizedImages">Details for each optimized or skipped image.</param>
+/// <param name="Validation">OpenXML validation status before and after.</param>
+/// <param name="Message">Human-readable status or error message.</param>
+public record ImageOptimizationResult(
+    bool Success,
+    string FilePath,
+    int ImagesProcessed,
+    int ImagesSkipped,
+    long TotalBytesBefore,
+    long TotalBytesAfter,
+    long TotalBytesSaved,
+    IReadOnlyList<OptimizedImageInfo> OptimizedImages,
+    ValidationStatus Validation,
+    string Message);

src/PptxMcp/PptxMcp.csproj

@@ -24,6 +24,7 @@
 
   <ItemGroup>
     <PackageReference Include="DocumentFormat.OpenXml" Version="3.5.1" />
+    <PackageReference Include="Magick.NET-Q8-AnyCPU" Version="14.2.0" />
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.5" />
     <PackageReference Include="ModelContextProtocol" Version="1.1.0" />
   </ItemGroup>